• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 춘계학술대회논문집
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• pp.145-149
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• 1997

General joystick using spring only has a vibration when operaor drops the joystick. If it is used as input of motorized wheelchair, its system have a serious problem which operator fall into dangerous situation. Therefore, In this paper proposed non-vibration joustick which control a motorized wheelchair. Non-vibration joystick was designed which return to origin point when operator drops joystick by mistake. Reflected force of non- vibration joystick is defined as addition displacement and variation rate. And each parameter has elasticity of spring and viscosity of DC servo motor. Through simulation for virtual environment, we found two coefficient to return origin point smoothly when a disabled person drops the joystick. In case of larger elastic coefficient of spring than viscous coefficient, we confirmed the result has the equal vibration of general joystick (under-damping). In opposite case, joystick returned to origin point with excessive force. As a application of non-vibration joystick, we experimented wall-following controlling. In this trial, we corroborated that joystick follows smoothly around the corridors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.100.6-100
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• 2002

The crane and the master-slave manipulators (MSM) are widely used as a remote handling device in nuclear facilities such as the hot cell. The equipment to be installed in the hot cell should be optimally placed within the workspace of the wall-mounted slave manipulator for the maintenance operation. Also, the slave manipulator with the end effectors should be properly positioned and oriented for the dedicated maintenance operation. Hence, the workspace and the motion of the slave manipulator, as well as, the remote operation task should be analyzed before installing the manipulators and the hot cell equipment. For this purpose, the 3D graphic simulator, which simulates the remote operation o...

• Asia pacific journal of information systems
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• 제26권1호
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• pp.124-142
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• 2016

Companies operating in social network platforms continue to improve and expand their marketing techniques. This study examines the practice of "gating", which involves virtual barriers between social network users and company content. Gates demand mandatory user endorsements, in the form of a Facebook "Likes", Twitter "retweets" etc., to gain access to company content, such as coupons and rewards,. Gating practices demand a mandatory endorsement before any content consumption takes place. Thus, while user endorsements are assumed to arise voluntarily from trusted known sources, gating practices would appear to violate this assumption. However, whether this violation lessens the effectiveness of gating practices still requires empirical validation. We investigate this question through the use of a unique panel data set that includes data on "like" endorsements obtained from a number of real-world Facebook business pages. Results of the study show that gating practices are effective for endorsement solicitation; however, gates may interfere with more traditional marketing activities.

• Interaction and multiscale mechanics
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• 제2권3호
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• pp.235-261
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• 2009

This study illustrates the differences between the elasto-plastic cap model and Lade's model with Cosserat rotation through the analyses of two large-scale geosynthetic-reinforced soil (GRS) retaining wall tests that were brought to failure using a monotonically increasing surcharge pressure. The finite element analyses with Lade's model were able to reasonably simulate the large-scale plane strain laboratory tests. On average, the finite element analyses gave reasonably good agreement with the experimental results in terms of global performances and shear band occurrences. In contrast, the cap model was not able to simulate the development of shear banding in the tests. In both test simulations the cap model predicted failure loads that were substantially less than the measured ones.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.540-540
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• 2000

This paper explores design and control methods of a surgical robot for total hip replacement surgery which can be easily maneuvered by a surgeon Like an advanced surgical tool. The 3-DOF in-parallel surgical robot is fixed directly onto patient's femur by the bone clamp during surgery. With the master/slave combined surgical robot, the surgeon can directly control the motion of the surgical robot with surgeon's experience and judgment during operation. For the easiness of operation, the master/slave combined robot is controlled using admittance control paradigm. And for the precise operation, the robot motion is restricted at the surgical boundary using virtual hard wall display.

• 한국소음진동공학회논문집
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• 제17권1호
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• pp.3-9
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• 2007

In this paper, a numerical case study is carried out on the hydroelastic vibration of rectangular plate with various fluid field. It is assumed that the tank wall is clamped along the plate edges. The VMM(virtual mass method) of Nastran is used for the simulation of fluid domain and calculating natural frequency of fluid-coupled structure. In this paper, natural frequencies are calculated and compared for rectangular plates with various fluid field such as infinite fluid and finite fluid, length change of finite fluid field and various fluid contacting conditions.

• ETRI Journal
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• 제38권6호
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• pp.1085-1094
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• 2016

In this work, we present interactive automultiscopic content with mobile surface haptics for multimodal interaction. Our system consists of a 40-view automultiscopic display and a tablet supporting surface haptics in an immersive room. Animated graphics are projected onto the walls of the room. The 40-view automultiscopic display is placed at the center of the front wall. The haptic tablet is installed at the mobile station to enable the user to interact with the tablet. The 40-view real-time rendering and multiplexing technology is applied by establishing virtual cameras in the convergence layout. Surface haptics rendering is synchronized with three-dimensional (3D) objects on the display for real-time haptic interaction. We conduct an experiment to evaluate user experiences of the proposed system. The results demonstrate that the system's multimodal interaction provides positive user experiences of immersion, control, user interface intuitiveness, and 3D effects.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권4호
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• pp.213-219
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• 2000

In this paper, a controller design method is proposed for haptic interface considering transparency and robust stability. For this, a performance index for the transparency as performance measure is defined in the points of impedance matching and the optimal solution which is minimizing the performance index is obtained by solving H2 optimal problem. In haptic interface, the modeling uncertainties can be restricted to that of haptic device. To implement the robust stabilizing haptic controller to the uncertainties of haptic device, a robust stable condition using H$\infty$ norm from small gain theorem is proposed. To verify the effectiveness of the proposed haptic controller design scheme, numerical examples and experimental results are illustrated for virtual wall consisting of stiffness and damping factor.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.1813-1818
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• 2014

햅틱 시스템에는 사용자인 인간이 항상 포함되므로, 인간 임피던스에 의한 시스템 안정성 분석이 필요하다. 특히, 일차 홀드 방식의 햅틱 시스템에 대한 인간 임피던스의 안정성 영향 분석이 미진하다. 본 논문에서는 선형 2차 시스템으로 모델화된 인간의 임피던스 모델을 포함하는, 일차 홀드 방식의 햅틱 시스템에 대한 안정성을 루드-후르비쯔 (Routh-Hurwitz)안정성 판별법을 이용하여 해석했다. 가상 벽 모델인 가상 스프링 상수 ($K_w$)의 안정성 영역과 인간 임피던스의 질량 ($M_h$), 댐핑 ($B_h$),그리고 스프링 상수 ($K_h$)와의 관계를 루드-후르비쯔 안정성 판별법을 이용하여 분석한 결과, 스프링 상수 ($K_h$)가 일정할 때 가상 스프링 상수 ($K_w$)는 인간 임피던스의 질량 ($M_h$)과 댐핑 ($B_h$)의 제곱근에 비례했다. 또한 인간 임피던스의 질량 ($M_h$)또는 댐핑 ($B_h$)가 일정할 때 가상 스프링 상수 ($K_w$)는 스프링 상수 ($K_h$)의 0.48배만큼 감소했다. 이를 종합하여 $K_w{\leq}54413{\sqrt{(M_h+M_d)(B_h+B_d)}}-0.486K_h$의 모델을 제안했고, 이론 값들과 제시된 모델로부터 계산된 값을 비교한 결과 평균적인 상대오차가 0.5%로 작게 나타났다. 제시된 모델이 인간 임피던스 모델과 가상 스프링 상수와의 관계를 비교적 잘 표현하고 있다.

• 디자인학연구
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• 제19권5호
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• pp.55-64
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• 2006

1980년대 중반이후 디지털 시스템이 자동차 디자인에 도입되면서 기존의 수작업을 통한 디자인 전개와 달리 개발기간을 단축시키는 디지털 프로세스로 급속하게 발전되고 있다. 이는 자동차 수출지역 확대에 따른 글로벌 디자인의 환경변화를 반영한 것이기도 하지만 고품질 다품종 자동차를 개발해야하는 당면 과제를 시간과 경제적인 면에서 효율적으로 활용하고자 함에 있다. 따라서 세계 각 자동차 제조사는 VR(virtual reality)스튜디오의 규모를 확대하여 자동차 실물 크기의 시각화 시스템을 구축하고, 각 지역별 디자인 스튜디오간의 동시간대 품평이 가능한 협업 체제에 주력하고 있다. 질적으로 향상된 품평은 기존의 디자인 검토와는 다른 실제 자동차가 출고되어 보여 지는 효과로 품평함으로써 자동차가 어떻게 보여 지는가를 이해하는 합리적 방법으로 평가받고 있으며, 어드밴스 제품이나 컨셉트카와 같이 빠른 결과를 확인하는 경우 효과적이다. 이외 대표적 장점은 개발기간 단축, 비용 절감, 단순 작업으로부터의 해방, 단기간의 다양한 디자인 제시, 컨셉트의 사실적 시각화 등이다. 자동차와 같이 제품의 크기가 큰 경우는 일반 디지털 하드웨어 시스템과 달리 파워-월을 통하여 실차 크기의 렌더링을 고해상도로 투사하며, 가상현실 공간인 케이브에서 디자인을 검토하기에 디지털 인프라 구축이라는 물리적 기간이 오랜 동안 소요되었다. 향후도 인프라 구축은 시스템 보완과 성능 향상의 지속적인 개선으로 결론을 정의 할 수는 없지만 디지털 디자인의 장점을 활용하고 단점을 보완하는 도약의 시기임은 분명하다. 따라서 디지털 강화요소를 기반으로 하는 디지털 디자인의 중요성을 인식하고 미래 자동차 개발에 효과적으로 적용될 수 있는 디지털의 체계적 활용을 연구하고자 한다.